| 1 |
Two Sum |
Easy |
✓ |
✓ |
| 2 |
Add Two Numbers |
Medium |
✓ |
✓ |
| 3 |
Longest Substring Without Repeating Characters |
Medium |
✓ |
✓ |
| 4 |
Median of Two Sorted Arrays |
Hard |
✓ |
|
| 5 |
Longest Palindromic Substring |
Medium |
✓ |
✓ |
| 6 |
ZigZag Conversion |
Medium |
✓ |
✓ |
| 7 |
Reverse Integer |
Easy |
✓ |
✓ |
| 8 |
String to Integer (atoi) |
Medium |
✓ |
✓ |
| 9 |
Palindrome Number |
Easy |
✓ |
✓ |
| 10 |
Regular Expression Matching |
Hard |
✓ |
✓ |
| 11 |
Container With Most Water |
Medium |
✓ |
✓ |
| 12 |
Integer to Roman |
Medium |
✓ |
✓ |
| 13 |
Roman to Integer |
Easy |
✓ |
✓ |
| 14 |
Longest Common Prefix |
Easy |
✓ |
✓ |
| 15 |
3Sum |
Medium |
✓ |
✓ |
| 16 |
3Sum Closest |
Medium |
✓ |
✓ |
| 17 |
Letter Combinations of a Phone Number |
Medium |
✓ |
✓ |
| 18 |
4Sum |
Medium |
✓ |
✓ |
| 19 |
Remove Nth Node From End of List |
Medium |
✓ |
✓ |
| 20 |
Valid Parentheses |
Easy |
✓ |
✓ |
| 21 |
Merge Two Sorted Lists |
Easy |
✓ |
✓ |
| 22 |
Generate Parentheses |
Medium |
✓ |
✓ |
| 23 |
Merge k Sorted Lists |
Hard |
✓ |
✓ |
| 24 |
Swap Nodes in Pairs |
Medium |
✓ |
✓ |
| 25 |
Reverse Nodes in k-Group |
Hard |
✓ |
|
| 26 |
Remove Duplicates from Sorted Array |
Easy |
✓ |
✓ |
| 27 |
Remove Element |
Easy |
✓ |
✓ |
| 28 |
Implement strStr() |
Easy |
✓ |
✓ |
| 29 |
Divide Two Integers |
Medium |
✓ |
|
| 30 |
Substring with Concatenation of All Words |
Hard |
✓ |
|
| 31 |
Next Permutation |
Medium |
✓ |
✓ |
| 32 |
Longest Valid Parentheses |
Hard |
✓ |
|
| 33 |
Search in Rotated Sorted Array |
Medium |
✓ |
|
| 34 |
Search for a Range |
Medium |
✓ |
|
| 35 |
Search Insert Position |
Easy |
✓ |
|
| 36 |
Valid Sudoku |
Medium |
✓ |
|
| 37 |
Sudoku Solver |
Hard |
✓ |
|
| 38 |
Count and Say |
Easy |
✓ |
|
| 39 |
Combination Sum |
Medium |
✓ |
|
| 40 |
Combination Sum II |
Medium |
✓ |
|
| 41 |
First Missing Positive |
Hard |
✓ |
|
| 42 |
Trapping Rain Water |
Hard |
✓ |
|
| 43 |
Multiply Strings |
Medium |
✓ |
|
| 44 |
Wildcard Matching |
Hard |
✓ |
|
| 45 |
Jump Game II |
Hard |
✓ |
|
| 46 |
Permutations |
Medium |
✓ |
✓ |
| 47 |
Permutations II |
Medium |
✓ |
|
| 48 |
Rotate Image |
Medium |
✓ |
|
| 49 |
Group Anagrams |
Medium |
✓ |
|
| 50 |
Pow(x, n) |
Medium |
✓ |
|
| 51 |
N-Queens |
Hard |
✓ |
|
| 52 |
N-Queens II |
Hard |
✓ |
|
| 53 |
Maximum Subarray |
Easy |
✓ |
|
| 54 |
Spiral Matrix |
Medium |
✓ |
|
| 55 |
Jump Game |
Medium |
✓ |
|
| 56 |
Merge Intervals |
Medium |
✓ |
|
| 57 |
Insert Interval |
Hard |
✓ |
|
| 58 |
Length of Last Word |
Easy |
✓ |
|
| 59 |
Spiral Matrix II |
Medium |
✓ |
|
| 60 |
Permutation Sequence |
Medium |
✓ |
|
| 61 |
Rotate List |
Medium |
✓ |
|
| 62 |
Unique Paths |
Medium |
✓ |
|
| 63 |
Unique Paths II |
Medium |
✓ |
|
| 64 |
Minimum Path Sum |
Medium |
✓ |
|
| 65 |
Valid Number |
Hard |
✓ |
|
| 66 |
Plus One |
Easy |
✓ |
|
| 67 |
Add Binary |
Easy |
✓ |
|
| 68 |
Text Justification |
Hard |
|
|
| 69 |
Sqrt(x) |
Easy |
✓ |
|
| 70 |
Climbing Stairs |
Easy |
✓ |
|
| 71 |
Simplify Path |
Medium |
✓ |
|
| 72 |
Edit Distance |
Hard |
✓ |
|
| 73 |
Set Matrix Zeroes |
Medium |
✓ |
|
| 74 |
Search a 2D Matrix |
Medium |
✓ |
|
| 75 |
Sort Colors |
Medium |
✓ |
|
| 76 |
Minimum Window Substring |
Hard |
|
|
| 77 |
Combinations |
Medium |
✓ |
|
| 78 |
Subsets |
Medium |
✓ |
|
| 79 |
Word Search |
Medium |
✓ |
|
| 80 |
Remove Duplicates from Sorted Array II |
Medium |
✓ |
|
| 81 |
Search in Rotated Sorted Array II |
Medium |
✓ |
|
| 82 |
Remove Duplicates from Sorted List II |
Medium |
✓ |
|
| 83 |
Remove Duplicates from Sorted List |
Easy |
✓ |
|
| 84 |
Largest Rectangle in Histogram |
Hard |
✓ |
|
| 85 |
Maximal Rectangle |
Hard |
|
|
| 86 |
Partition List |
Medium |
✓ |
|
| 87 |
Scramble String |
Hard |
|
|
| 88 |
Merge Sorted Array |
Easy |
✓ |
|
| 89 |
Gray Code |
Medium |
✓ |
|
| 90 |
Subsets II |
Medium |
✓ |
|
| 91 |
Decode Ways |
Medium |
✓ |
|
| 92 |
Reverse Linked List II |
Medium |
✓ |
|
| 93 |
Restore IP Addresses |
Medium |
✓ |
|
| 94 |
Binary Tree Inorder Traversal |
Medium |
✓ |
|
| 95 |
Unique Binary Search Trees II |
Medium |
✓ |
|
| 96 |
Unique Binary Search Trees |
Medium |
✓ |
|
| 97 |
Interleaving String |
Hard |
|
|
| 98 |
Validate Binary Search Tree |
Medium |
✓ |
|
| 99 |
Recover Binary Search Tree |
Hard |
|
|
| 100 |
Same Tree |
Easy |
✓ |
|
| 101 |
Symmetric Tree |
Easy |
✓ |
|
| 102 |
Binary Tree Level Order Traversal |
Medium |
✓ |
|
| 103 |
Binary Tree Zigzag Level Order Traversal |
Medium |
✓ |
|
| 104 |
Maximum Depth of Binary Tree |
Easy |
✓ |
|
| 105 |
Construct Binary Tree from Preorder and Inorder Traversal |
Medium |
✓ |
|
| 106 |
Construct Binary Tree from Inorder and Postorder Traversal |
Medium |
✓ |
|
| 107 |
Binary Tree Level Order Traversal II |
Easy |
✓ |
|
| 108 |
Convert Sorted Array to Binary Search Tree |
Easy |
✓ |
|
| 109 |
Convert Sorted List to Binary Search Tree |
Medium |
✓ |
|
| 110 |
Balanced Binary Tree |
Easy |
✓ |
|
| 111 |
Minimum Depth of Binary Tree |
Easy |
✓ |
|
| 112 |
Path Sum |
Easy |
✓ |
|
| 113 |
Path Sum II |
Medium |
✓ |
|
| 114 |
Flatten Binary Tree to Linked List |
Medium |
✓ |
|
| 115 |
Distinct Subsequences |
Hard |
✓ |
|
| 116 |
Populating Next Right Pointers in Each Node |
Medium |
✓ |
|
| 117 |
Populating Next Right Pointers in Each Node II |
Medium |
✓ |
|
| 118 |
Pascal’s Triangle |
Easy |
✓ |
|
| 119 |
Pascal’s Triangle II |
Easy |
✓ |
|
| 120 |
Triangle |
Medium |
✓ |
|
| 121 |
Best Time to Buy and Sell Stock |
Easy |
✓ |
|
| 122 |
Best Time to Buy and Sell Stock II |
Easy |
✓ |
|
| 123 |
Best Time to Buy and Sell Stock III |
Hard |
✓ |
|
| 124 |
Binary Tree Maximum Path Sum |
Hard |
✓ |
|
| 125 |
Valid Palindrome |
Easy |
✓ |
|
| 126 |
Word Ladder II |
Hard |
✓ |
|
| 127 |
Word Ladder |
Medium |
✓ |
|
| 128 |
Longest Consecutive Sequence |
Hard |
|
|
| 129 |
Sum Root to Leaf Numbers |
Medium |
✓ |
|
| 130 |
Surrounded Regions |
Medium |
✓ |
|
| 131 |
Palindrome Partitioning |
Medium |
✓ |
|
| 132 |
Palindrome Partitioning II |
Hard |
✓ |
|
| 133 |
Clone Graph |
Medium |
✓ |
|
| 134 |
Gas Station |
Medium |
✓ |
|
| 135 |
Candy |
Hard |
|
|
| 136 |
Single Number |
Easy |
✓ |
|
| 137 |
Single Number II |
Medium |
✓ |
|
| 138 |
Copy List with Random Pointer |
Medium |
✓ |
|
| 139 |
Word Break |
Medium |
✓ |
|
| 140 |
Word Break II |
Hard |
|
|
| 141 |
Linked List Cycle |
Easy |
✓ |
|
| 142 |
Linked List Cycle II |
Medium |
✓ |
|
| 143 |
Reorder List |
Medium |
✓ |
|
| 144 |
Binary Tree Preorder Traversal |
Medium |
✓ |
|
| 145 |
Binary Tree Postorder Traversal |
Hard |
|
|
| 146 |
LRU Cache |
Hard |
✓ |
|
| 147 |
Insertion Sort List |
Medium |
✓ |
|
| 148 |
Sort List |
Medium |
✓ |
|
| 149 |
Max Points on a Line |
Hard |
✓ |
|
| 150 |
Evaluate Reverse Polish Notation |
Medium |
|
|
| 151 |
Reverse Words in a String |
Medium |
✓ |
|
| 152 |
Maximum Product Subarray |
Medium |
|
|
| 153 |
Find Minimum in Rotated Sorted Array |
Medium |
✓ |
|
| 154 |
Find Minimum in Rotated Sorted Array II |
Hard |
|
|
| 155 |
Min Stack |
Easy |
✓ |
|
| 156 |
Binary Tree Upside Down |
Medium |
✓ |
|
| 157 |
Read N Characters Given Read4 |
Easy |
✓ |
|
| 158 |
Read N Characters Given Read4 II - Call multiple times |
Hard |
|
|
| 159 |
Longest Substring with At Most Two Distinct Characters |
Hard |
|
|
| 160 |
Intersection of Two Linked Lists |
Easy |
✓ |
|
| 161 |
One Edit Distance |
Medium |
✓ |
|
| 162 |
Find Peak Element |
Medium |
✓ |
|
| 163 |
Missing Ranges |
Medium |
✓ |
|
| 164 |
Maximum Gap |
Hard |
✓ |
|
| 165 |
Compare Version Numbers |
Medium |
✓ |
|
| 166 |
Fraction to Recurring Decimal |
Medium |
✓ |
|
| 167 |
Two Sum II - Input array is sorted |
Easy |
✓ |
|
| 168 |
Excel Sheet Column Title |
Easy |
✓ |
|
| 169 |
Majority Element |
Easy |
✓ |
|
| 170 |
Two Sum III - Data structure design |
Easy |
✓ |
|
| 171 |
Excel Sheet Column Number |
Easy |
✓ |
|
| 172 |
Factorial Trailing Zeroes |
Easy |
✓ |
|
| 173 |
Binary Search Tree Iterator |
Medium |
✓ |
|
| 174 |
Dungeon Game |
Hard |
|
|
| 175 |
Combine Two Tables |
Easy |
|
|
| 176 |
Second Highest Salary |
Easy |
|
|
| 177 |
Nth Highest Salary |
Medium |
|
|
| 178 |
Rank Scores |
Medium |
|
|
| 179 |
Largest Number |
Medium |
|
|
| 180 |
Consecutive Numbers |
Medium |
|
|
| 181 |
Employees Earning More Than Their Managers |
Easy |
|
|
| 182 |
Duplicate Emails |
Easy |
|
|
| 183 |
Customers Who Never Order |
Easy |
|
|
| 184 |
Department Highest Salary |
Medium |
|
|
| 185 |
Department Top Three Salaries |
Hard |
|
|
| 186 |
Reverse Words in a String II |
Medium |
|
|
| 187 |
Repeated DNA Sequences |
Medium |
✓ |
|
| 188 |
Best Time to Buy and Sell Stock IV |
Hard |
✓ |
|
| 189 |
Rotate Array |
Easy |
✓ |
|
| 190 |
Reverse Bits |
Easy |
✓ |
|
| 191 |
Number of 1 Bits |
Easy |
✓ |
|
| 192 |
Word Frequency |
Medium |
|
|
| 193 |
Valid Phone Numbers |
Easy |
|
|
| 194 |
Transpose File |
Medium |
|
|
| 195 |
Tenth Line |
Easy |
|
|
| 196 |
Delete Duplicate Emails |
Easy |
|
|
| 197 |
Rising Temperature |
Easy |
|
|
| 198 |
House Robber |
Easy |
✓ |
|
| 199 |
Binary Tree Right Side View |
Medium |
|
|
| 200 |
Number of Islands |
Medium |
✓ |
|
| 201 |
Bitwise AND of Numbers Range |
Medium |
|
|
| 202 |
Happy Number |
Easy |
✓ |
|
| 203 |
Remove Linked List Elements |
Easy |
✓ |
|
| 204 |
Count Primes |
Easy |
✓ |
|
| 205 |
Isomorphic Strings |
Easy |
✓ |
|
| 206 |
Reverse Linked List |
Easy |
✓ |
|
| 207 |
Course Schedule |
Medium |
✓ |
|
| 208 |
Implement Trie (Prefix Tree) |
Medium |
✓ |
|
| 209 |
Minimum Size Subarray Sum |
Medium |
|
|
| 210 |
Course Schedule II |
Medium |
|
|
| 211 |
Add and Search Word - Data structure design |
Medium |
✓ |
|
| 212 |
Word Search II |
Hard |
✓ |
|
| 213 |
House Robber II |
Medium |
✓ |
|
| 214 |
Shortest Palindrome |
Hard |
|
|
| 215 |
Kth Largest Element in an Array |
Medium |
✓ |
|
| 216 |
Combination Sum III |
Medium |
✓ |
|
| 217 |
Contains Duplicate |
Easy |
✓ |
|
| 218 |
The Skyline Problem |
Hard |
|
|
| 219 |
Contains Duplicate II |
Easy |
✓ |
|
| 220 |
Contains Duplicate III |
Medium |
✓ |
|
| 221 |
Maximal Square |
Medium |
|
|
| 222 |
Count Complete Tree Nodes |
Medium |
|
|
| 223 |
Rectangle Area |
Medium |
✓ |
|
| 224 |
Basic Calculator |
Hard |
|
|
| 225 |
Implement Stack using Queues |
Easy |
✓ |
|
| 226 |
Invert Binary Tree |
Easy |
✓ |
|
| 227 |
Basic Calculator II |
Medium |
|
|
| 228 |
Summary Ranges |
Medium |
✓ |
|
| 229 |
Majority Element II |
Medium |
|
|
| 230 |
Kth Smallest Element in a BST |
Medium |
✓ |
|
| 231 |
Power of Two |
Easy |
✓ |
|
| 232 |
Implement Queue using Stacks |
Easy |
✓ |
|
| 233 |
Number of Digit One |
Hard |
|
|
| 234 |
Palindrome Linked List |
Easy |
✓ |
|
| 235 |
Lowest Common Ancestor of a Binary Search Tree |
Easy |
✓ |
|
| 236 |
Lowest Common Ancestor of a Binary Tree |
Medium |
✓ |
|
| 237 |
Delete Node in a Linked List |
Easy |
✓ |
|
| 238 |
Product of Array Except Self |
Medium |
✓ |
|
| 239 |
Sliding Window Maximum |
Hard |
✓ |
|
| 240 |
Search a 2D Matrix II |
Medium |
✓ |
|
| 241 |
Different Ways to Add Parentheses |
Medium |
|
|
| 242 |
Valid Anagram |
Easy |
✓ |
|
| 243 |
Shortest Word Distance |
Easy |
✓ |
|
| 244 |
Shortest Word Distance II |
Medium |
✓ |
|
| 245 |
Shortest Word Distance III |
Medium |
✓ |
|
| 246 |
Strobogrammatic Number |
Easy |
✓ |
|
| 247 |
Strobogrammatic Number II |
Medium |
|
|
| 248 |
Strobogrammatic Number III |
Hard |
|
|
| 249 |
Group Shifted Strings |
Medium |
✓ |
|
| 250 |
Count Univalue Subtrees |
Medium |
|
|
| 251 |
Flatten 2D Vector |
Medium |
✓ |
|
| 252 |
Meeting Rooms |
Easy |
✓ |
|
| 253 |
Meeting Rooms II |
Medium |
|
|
| 254 |
Factor Combinations |
Medium |
|
|
| 255 |
Verify Preorder Sequence in Binary Search Tree |
Medium |
✓ |
|
| 256 |
Paint House |
Easy |
✓ |
|
| 257 |
Binary Tree Paths |
Easy |
✓ |
|
| 258 |
Add Digits |
Easy |
✓ |
|
| 259 |
3Sum Smaller |
Medium |
|
|
| 260 |
Single Number III |
Medium |
✓ |
|
| 261 |
Graph Valid Tree |
Medium |
✓ |
|
| 262 |
Trips and Users |
Hard |
|
|
| 263 |
Ugly Number |
Easy |
✓ |
|
| 264 |
Ugly Number II |
Medium |
✓ |
|
| 265 |
Paint House II |
Hard |
✓ |
|
| 266 |
Palindrome Permutation |
Easy |
✓ |
|
| 267 |
Palindrome Permutation II |
Medium |
|
|
| 268 |
Missing Number |
Easy |
✓ |
|
| 269 |
Alien Dictionary |
Hard |
✓ |
✓ |
| 270 |
Closest Binary Search Tree Value |
Easy |
✓ |
|
| 271 |
Encode and Decode Strings |
Medium |
|
|
| 272 |
Closest Binary Search Tree Value II |
Hard |
|
|
| 273 |
Integer to English Words |
Hard |
|
|
| 274 |
H-Index |
Medium |
✓ |
|
| 275 |
H-Index II |
Medium |
✓ |
|
| 276 |
Paint Fence |
Easy |
✓ |
|
| 277 |
Find the Celebrity |
Medium |
|
|
| 278 |
First Bad Version |
Easy |
✓ |
|
| 279 |
Perfect Squares |
Medium |
✓ |
|
| 280 |
Wiggle Sort |
Medium |
✓ |
|
| 281 |
Zigzag Iterator |
Medium |
✓ |
|
| 282 |
Expression Add Operators |
Hard |
|
|
| 283 |
Move Zeroes |
Easy |
✓ |
|
| 284 |
Peeking Iterator |
Medium |
✓ |
|
| 285 |
Inorder Successor in BST |
Medium |
✓ |
|
| 286 |
Walls and Gates |
Medium |
|
|
| 287 |
Find the Duplicate Number |
Medium |
|
|
| 288 |
Unique Word Abbreviation |
Medium |
✓ |
|
| 289 |
Game of Life |
Medium |
✓ |
|
| 290 |
Word Pattern |
Easy |
✓ |
|
| 291 |
Word Pattern II |
Hard |
|
|
| 292 |
Nim Game |
Easy |
✓ |
|
| 293 |
Flip Game |
Easy |
✓ |
|
| 294 |
Flip Game II |
Medium |
✓ |
|
| 295 |
Find Median from Data Stream |
Hard |
✓ |
|
| 296 |
Best Meeting Point |
Hard |
|
|
| 297 |
Serialize and Deserialize Binary Tree |
Hard |
|
|
| 298 |
Binary Tree Longest Consecutive Sequence |
Medium |
|
|
| 299 |
Bulls and Cows |
Medium |
✓ |
|
| 300 |
Longest Increasing Subsequence |
Medium |
✓ |
|
| 301 |
Remove Invalid Parentheses |
Hard |
|
|
| 302 |
Smallest Rectangle Enclosing Black Pixels |
Hard |
|
|
| 303 |
Range Sum Query - Immutable |
Easy |
✓ |
|
| 304 |
Range Sum Query 2D - Immutable |
Medium |
|
|
| 305 |
Number of Islands II |
Hard |
|
|
| 306 |
Additive Number |
Medium |
|
|
| 307 |
Range Sum Query - Mutable |
Medium |
|
|
| 308 |
Range Sum Query 2D - Mutable |
Hard |
|
|
| 309 |
Best Time to Buy and Sell Stock with Cooldown |
Medium |
✓ |
|
| 310 |
Minimum Height Trees |
Medium |
|
|
| 311 |
Sparse Matrix Multiplication |
Medium |
✓ |
|
| 312 |
Burst Balloons |
Hard |
|
|
| 313 |
Super Ugly Number |
Medium |
✓ |
|
| 314 |
Binary Tree Vertical Order Traversal |
Medium |
|
|
| 315 |
Count of Smaller Numbers After Self |
Hard |
|
|
| 316 |
Remove Duplicate Letters |
Hard |
|
|
| 317 |
Shortest Distance from All Buildings |
Hard |
|
|
| 318 |
Maximum Product of Word Lengths |
Medium |
✓ |
|
| 319 |
Bulb Switcher |
Medium |
✓ |
|
| 320 |
Generalized Abbreviation |
Medium |
✓ |
|
| 321 |
Create Maximum Number |
Hard |
|
|
| 322 |
Coin Change |
Medium |
✓ |
|
| 323 |
Number of Connected Components in an Undirected Graph |
Medium |
✓ |
|
| 324 |
Wiggle Sort II |
Medium |
|
|
| 325 |
Maximum Size Subarray Sum Equals k |
Medium |
✓ |
|
| 326 |
Power of Three |
Easy |
✓ |
|
| 327 |
Count of Range Sum |
Hard |
|
|
| 328 |
Odd Even Linked List |
Medium |
✓ |
|
| 329 |
Longest Increasing Path in a Matrix |
Hard |
|
|
| 330 |
Patching Array |
Hard |
|
|
| 331 |
Verify Preorder Serialization of a Binary Tree |
Medium |
|
|
| 332 |
Reconstruct Itinerary |
Medium |
|
|
| 333 |
Largest BST Subtree |
Medium |
|
|
| 334 |
Increasing Triplet Subsequence |
Medium |
|
|
| 335 |
Self Crossing |
Hard |
|
|
| 336 |
Palindrome Pairs |
Hard |
|
|
| 337 |
House Robber III |
Medium |
✓ |
|
| 338 |
Counting Bits |
Medium |
✓ |
|
| 339 |
Nested List Weight Sum |
Easy |
✓ |
|
| 340 |
Longest Substring with At Most K Distinct Characters |
Hard |
|
|
| 341 |
Flatten Nested List Iterator |
Medium |
✓ |
|
| 342 |
Power of Four |
Easy |
✓ |
|
| 343 |
Integer Break |
Medium |
✓ |
|
| 344 |
Reverse String |
Easy |
✓ |
|
| 345 |
Reverse Vowels of a String |
Easy |
✓ |
|
| 346 |
Moving Average from Data Stream |
Easy |
✓ |
|
| 347 |
Top K Frequent Elements |
Medium |
✓ |
|
| 348 |
Design Tic-Tac-Toe |
Medium |
✓ |
|
| 349 |
Intersection of Two Arrays |
Easy |
✓ |
|
| 350 |
Intersection of Two Arrays II |
Easy |
✓ |
|
| 351 |
Android Unlock Patterns |
Medium |
|
|
| 352 |
Data Stream as Disjoint Intervals |
Hard |
|
|
| 353 |
Design Snake Game |
Medium |
✓ |
|
| 354 |
Russian Doll Envelopes |
Hard |
✓ |
|
| 355 |
Design Twitter |
Medium |
|
|
| 356 |
Line Reflection |
Medium |
✓ |
|
| 357 |
Count Numbers with Unique Digits |
Medium |
✓ |
|
| 358 |
Rearrange String k Distance Apart |
Hard |
|
|
| 359 |
Logger Rate Limiter |
Easy |
✓ |
|
| 360 |
Sort Transformed Array |
Medium |
✓ |
|
| 361 |
Bomb Enemy |
Medium |
|
|
| 362 |
Design Hit Counter |
Medium |
✓ |
|
| 363 |
Max Sum of Rectangle No Larger Than K |
Hard |
|
|
| 364 |
Nested List Weight Sum II |
Medium |
✓ |
|
| 365 |
Water and Jug Problem |
Medium |
✓ |
|
| 366 |
Find Leaves of Binary Tree |
Medium |
✓ |
|
| 367 |
Valid Perfect Square |
Easy |
✓ |
|
| 368 |
Largest Divisible Subset |
Medium |
|
|
| 369 |
Plus One Linked List |
Medium |
✓ |
|
| 370 |
Range Addition |
Medium |
✓ |
|
| 371 |
Sum of Two Integers |
Easy |
✓ |
|
| 372 |
Super Pow |
Medium |
|
|
| 373 |
Find K Pairs with Smallest Sums |
Medium |
|
|
| 374 |
Guess Number Higher or Lower |
Easy |
✓ |
|
| 375 |
Guess Number Higher or Lower II |
Medium |
|
|
| 376 |
Wiggle Subsequence |
Medium |
|
|
| 377 |
Combination Sum IV |
Medium |
✓ |
|
| 378 |
Kth Smallest Element in a Sorted Matrix |
Medium |
✓ |
|
| 379 |
Design Phone Directory |
Medium |
✓ |
|
| 380 |
Insert Delete GetRandom O(1) |
Medium |
|
|
| 381 |
Insert Delete GetRandom O(1) - Duplicates allowed |
Hard |
|
|
| 382 |
Linked List Random Node |
Medium |
✓ |
|
| 383 |
Ransom Note |
Easy |
✓ |
|
| 384 |
Shuffle an Array |
Medium |
✓ |
|
| 385 |
Mini Parser |
Medium |
|
|
| 386 |
Lexicographical Numbers |
Medium |
✓ |
|
| 387 |
First Unique Character in a String |
Easy |
✓ |
|
| 388 |
Longest Absolute File Path |
Medium |
|
|
| 389 |
Find the Difference |
Easy |
✓ |
|
| 390 |
Elimination Game |
Medium |
|
|
| 391 |
Perfect Rectangle |
Hard |
|
|
| 392 |
Is Subsequence |
Medium |
✓ |
|
| 393 |
UTF-8 Validation |
Medium |
✓ |
|
| 394 |
Decode String |
Medium |
|
|
| 395 |
Longest Substring with At Least K Repeating Characters |
Medium |
✓ |
|
| 396 |
Rotate Function |
Medium |
✓ |
|
| 397 |
Integer Replacement |
Medium |
✓ |
|
| 398 |
Random Pick Index |
Medium |
|
|
| 399 |
Evaluate Division |
Medium |
|
|
| 400 |
Nth Digit |
Easy |
✓ |
|
| 401 |
Binary Watch |
Easy |
✓ |
|
| 402 |
Remove K Digits |
Medium |
✓ |
|
| 403 |
Frog Jump |
Hard |
|
|
| 404 |
Sum of Left Leaves |
Easy |
✓ |
|
| 405 |
Convert a Number to Hexadecimal |
Easy |
✓ |
|
| 406 |
Queue Reconstruction by Height |
Medium |
|
|
| 407 |
Trapping Rain Water II |
Hard |
|
|
| 408 |
Valid Word Abbreviation |
Easy |
✓ |
|
| 409 |
Longest Palindrome |
Easy |
✓ |
|
| 410 |
Split Array Largest Sum |
Hard |
|
|
| 411 |
Minimum Unique Word Abbreviation |
Hard |
|
|
| 412 |
Fizz Buzz |
Easy |
✓ |
|
| 413 |
Arithmetic Slices |
Medium |
✓ |
|
| 414 |
Third Maximum Number |
Easy |
|
|
| 415 |
Add Strings |
Easy |
✓ |
|
| 416 |
Partition Equal Subset Sum |
Medium |
|
|
| 417 |
Pacific Atlantic Water Flow |
Medium |
|
|
| 418 |
Sentence Screen Fitting |
Medium |
|
|
| 419 |
Battleships in a Board |
Medium |
✓ |
|
| 420 |
Strong Password Checker |
Hard |
|
|
| 421 |
Maximum XOR of Two Numbers in an Array |
Medium |
|
|
| 422 |
Valid Word Square |
Easy |
|
|
| 423 |
Reconstruct Original Digits from English |
Medium |
|
|
| 424 |
Longest Repeating Character Replacement |
Medium |
|
|
| 425 |
Word Squares |
Hard |
|
|
| 432 |
All O`one Data Structure |
Hard |
|
|
| 433 |
Minimum Genetic Mutation |
Medium |
|
|
| 434 |
Number of Segments in a String |
Easy |
|
|
| 435 |
Non-overlapping Intervals |
Medium |
|
|
| 436 |
Find Right Interval |
Medium |
|
|
| 437 |
Path Sum III |
Easy |
|
|
| 438 |
Find All Anagrams in a String |
Easy |
|
|
| 439 |
Ternary Expression Parser |
Medium |
|
|
| 440 |
K-th Smallest in Lexicographical Order |
Hard |
|
|
| 441 |
Arranging Coins |
Easy |
✓ |
|
| 442 |
Find All Duplicates in an Array |
Medium |
|
|
| 443 |
String Compression |
Easy |
|
|
| 444 |
Sequence Reconstruction |
Medium |
|
|
| 445 |
Add Two Numbers II |
Medium |
|
|
| 446 |
Arithmetic Slices II - Subsequence |
Hard |
|
|
| 447 |
Number of Boomerangs |
Easy |
|
|
| 448 |
Find All Numbers Disappeared in an Array |
Easy |
✓ |
|
| 449 |
Serialize and Deserialize BST |
Medium |
|
|
| 450 |
Delete Node in a BST |
Medium |
|
|
| 451 |
Sort Characters By Frequency |
Medium |
|
|
| 452 |
Minimum Number of Arrows to Burst Balloons |
Medium |
|
|
| 453 |
Minimum Moves to Equal Array Elements |
Easy |
✓ |
|
| 454 |
4Sum II |
Medium |
|
|
| 455 |
Assign Cookies |
Easy |
✓ |
|
| 456 |
132 Pattern |
Medium |
|
|
| 457 |
Circular Array Loop |
Medium |
|
|
| 458 |
Poor Pigs |
Easy |
|
|
| 459 |
Repeated Substring Pattern |
Easy |
|
|
| 460 |
LFU Cache |
Hard |
|
|
| 461 |
Hamming Distance |
Easy |
✓ |
|
| 462 |
Minimum Moves to Equal Array Elements II |
Medium |
✓ |
|
| 463 |
Island Perimeter |
Easy |
|
|
| 464 |
Can I Win |
Medium |
|
|
| 465 |
Optimal Account Balancing |
Hard |
|
|
| 466 |
Count The Repetitions |
Hard |
|
|
| 467 |
Unique Substrings in Wraparound String |
Medium |
|
|
| 468 |
Validate IP Address |
Medium |
|
|
| 469 |
Convex Polygon |
Medium |
|
|
| 471 |
Encode String with Shortest Length |
Hard |
|
|
| 472 |
Concatenated Words |
Hard |
|
|
| 473 |
Matchsticks to Square |
Medium |
|
|
| 474 |
Ones and Zeroes |
Medium |
|
|
| 475 |
Heaters |
Easy |
✓ |
|
| 476 |
Number Complement |
Easy |
✓ |
|
| 477 |
Total Hamming Distance |
Medium |
|
|
| 479 |
Largest Palindrome Product |
Easy |
|
|
| 480 |
Sliding Window Median |
Hard |
|
|
| 481 |
Magical String |
Medium |
|
|
| 482 |
License Key Formatting |
Medium |
|
|
| 483 |
Smallest Good Base |
Hard |
|
|
| 484 |
Find Permutation |
Medium |
|
|
| 485 |
Max Consecutive Ones |
Easy |
✓ |
|
| 486 |
Predict the Winner |
Medium |
|
|
| 487 |
Max Consecutive Ones II |
Medium |
|
|
| 488 |
Zuma Game |
Hard |
|
|
| 490 |
The Maze |
Medium |
|
|
| 491 |
Increasing Subsequences |
Medium |
|
|
| 492 |
Construct the Rectangle |
Easy |
|
|
| 493 |
Reverse Pairs |
Hard |
|
|
| 494 |
Target Sum |
Medium |
|
|
| 495 |
Teemo Attacking |
Medium |
|
|
| 496 |
Next Greater Element I |
Easy |
|
|
| 498 |
Diagonal Traverse |
Medium |
|
|
| 499 |
The Maze III |
Hard |
|
|
| 500 |
Keyboard Row |
Easy |
|
|
| 501 |
Find Mode in Binary Search Tree |
Easy |
|
|
| 502 |
IPO |
Hard |
|
|
| 503 |
Next Greater Element II |
Medium |
|
|
| 504 |
Base 7 |
Easy |
|
|
| 505 |
The Maze II |
Medium |
|
|
| 506 |
Relative Ranks |
Easy |
|
|
| 507 |
Perfect Number |
Easy |
|
|
| 508 |
Most Frequent Subtree Sum |
Medium |
|
|
| 513 |
Find Bottom Left Tree Value |
Medium |
|
|
| 514 |
Freedom Trail |
Hard |
|
|
| 515 |
Find Largest Value in Each Tree Row |
Medium |
|
|
| 516 |
Longest Palindromic Subsequence |
Medium |
|
|
| 517 |
Super Washing Machines |
Hard |
|
|
| 518 |
Coin Change 2 |
Medium |
|
|
| 520 |
Detect Capital |
Easy |
|
|
| 521 |
Longest Uncommon Subsequence I |
Easy |
|
|
| 522 |
Longest Uncommon Subsequence II |
Medium |
|
|
| 523 |
Continuous Subarray Sum |
Medium |
|
|
| 524 |
Longest Word in Dictionary through Deleting |
Medium |
|
|
| 525 |
Contiguous Array |
Medium |
|
|
| 526 |
Beautiful Arrangement |
Medium |
|
|
| 527 |
Word Abbreviation |
Hard |
|
|
| 529 |
Minesweeper |
Medium |
✓ |
|
| 530 |
Minimum Absolute Difference in BST |
Easy |
|
|
| 531 |
Lonely Pixel I |
Medium |
|
|
| 532 |
K-diff Pairs in an Array |
Easy |
|
|
| 533 |
Lonely Pixel II |
Medium |
|
|
| 534 |
Design TinyURL |
Medium |
|
|
| 535 |
Encode and Decode TinyURL |
Medium |
✓ |
|
| 536 |
Construct Binary Tree from String |
Medium |
|
|
| 537 |
Complex Number Multiplication |
Medium |
|
|
| 538 |
Convert BST to Greater Tree |
Easy |
|
|
| 539 |
Minimum Time Difference |
Medium |
|
|
| 540 |
Single Element in a Sorted Array |
Medium |
|
|
| 541 |
Reverse String II |
Easy |
|
|
| 542 |
01 Matrix |
Medium |
|
|
| 543 |
Diameter of Binary Tree |
Easy |
|
|
| 544 |
Output Contest Matches |
Medium |
|
|
| 545 |
Boundary of Binary Tree |
Medium |
|
|
| 546 |
Remove Boxes |
Hard |
|
|
| 547 |
Friend Circles |
Medium |
|
|
| 548 |
Split Array with Equal Sum |
Medium |
|
|
| 549 |
Binary Tree Longest Consecutive Sequence II |
Medium |
|
|
| 551 |
Student Attendance Record I |
Easy |
|
|
| 552 |
Student Attendance Record II |
Hard |
|
|
| 553 |
Optimal Division |
Medium |
|
|
| 554 |
Brick Wall |
Medium |
|
|
| 555 |
Split Concatenated Strings |
Medium |
|
|
| 556 |
Next Greater Element III |
Medium |
|
|
| 557 |
Reverse Words in a String III |
Easy |
|
|
| 560 |
Subarray Sum Equals K |
Medium |
|
|
| 561 |
Array Partition I |
Easy |
|
|
| 562 |
Longest Line of Consecutive One in Matrix |
Medium |
|
|
| 563 |
Binary Tree Tilt |
Easy |
|
|
| 564 |
Find the Closest Palindrome |
Hard |
|
|
| 566 |
Reshape the Matrix |
Easy |
|
|
| 567 |
Permutation in String |
Medium |
|
|
| 568 |
Maximum Vacation Days |
Hard |
|
|
| 569 |
Median Employee Salary |
Hard |
|
|
| 570 |
Managers with at Least 5 Direct Reports |
Medium |
|
|
| 571 |
Find Median Given Frequency of Numbers |
Hard |
|
|
| 572 |
Subtree of Another Tree |
Easy |
|
|
| 573 |
Squirrel Simulation |
Medium |
|
|
| 574 |
Winning Candidate |
Medium |
|
|
| 575 |
Distribute Candies |
Easy |
|
|
| 576 |
Out of Boundary Paths |
Medium |
|
|
| 577 |
Employee Bonus |
Easy |
|
|
| 578 |
Get Highest Answer Rate Question |
Medium |
|
|
| 579 |
Find Cumulative Salary of an Employee |
Hard |
|
|
| 580 |
Count Student Number in Departments |
Medium |
|
|
| 581 |
Shortest Unsorted Continuous Subarray |
Easy |
|
|
| 582 |
Kill Process |
Medium |
|
|
| 583 |
Delete Operation for Two Strings |
Medium |
|
|
| 584 |
Find Customer Referee |
Easy |
|
|
| 585 |
Investments in 2016 |
Medium |
|
|
| 586 |
Customer Placing the Largest Number of Orders |
Easy |
|
|
| 587 |
Erect the Fence |
Hard |
|
|
| 588 |
Design In-Memory File System |
Hard |
|
|
| 591 |
Tag Validator |
Hard |
|
|
| 592 |
Fraction Addition and Subtraction |
Medium |
|
|
| 593 |
Valid Square |
Medium |
|
|
| 594 |
Longest Harmonious Subsequence |
Easy |
|
|
| 595 |
Big Countries |
Easy |
|
|
| 596 |
Classes More Than 5 Students |
Easy |
|
|
| 597 |
Friend Requests I: Overall Acceptance Rate |
Easy |
|
|
| 598 |
Range Addition II |
Easy |
|
|
| 599 |
Minimum Index Sum of Two Lists |
Easy |
|
|
| 600 |
Non-negative Integers without Consecutive Ones |
Hard |
|
|
| 601 |
Human Traffic of Stadium |
Hard |
|
|
| 602 |
Friend Requests II: Who Has the Most Friends |
Medium |
|
|
| 603 |
Consecutive Available Seats |
Easy |
|
|
| 604 |
Design Compressed String Iterator |
Easy |
|
|
| 605 |
Can Place Flowers |
Easy |
|
|
| 606 |
Construct String from Binary Tree |
Easy |
|
|
| 607 |
Sales Person |
Easy |
|
|
| 608 |
Tree Node |
Medium |
|
|
| 609 |
Find Duplicate File in System |
Medium |
|
|
| 610 |
Triangle Judgement |
Easy |
|
|
| 611 |
Valid Triangle Number |
Medium |
|
|
| 612 |
Shortest Distance in a Plane |
Medium |
|
|
| 613 |
Shortest Distance in a Line |
Easy |
|
|
| 614 |
Second Degree Follower |
Medium |
|
|
| 615 |
Average Salary: Departments VS Company |
Hard |
|
|
| 616 |
Add Bold Tag in String |
Medium |
✓ |
|
| 617 |
Merge Two Binary Trees |
Easy |
|
|
| 618 |
Students Report By Geography |
Hard |
|
|
| 619 |
Biggest Single Number |
Easy |
|
|
| 620 |
Not Boring Movies |
Easy |
|
|
| 621 |
Task Scheduler |
Medium |
|
|
| 623 |
Add One Row to Tree |
Medium |
|
|
| 624 |
Maximum Distance in Arrays |
Easy |
|
|
| 625 |
Minimum Factorization |
Medium |
|
|
| 626 |
Exchange Seats |
Medium |
|
|
| 627 |
Swap Salary |
Easy |
|
|
| 628 |
Maximum Product of Three Numbers |
Easy |
|
|
| 629 |
K Inverse Pairs Array |
Hard |
|
|
| 630 |
Course Schedule III |
Hard |
|
|
| 631 |
Design Excel Sum Formula |
Hard |
|
|
| 632 |
Smallest Range |
Hard |
|
|
| 633 |
Sum of Square Numbers |
Easy |
|
|
| 634 |
Find the Derangement of An Array |
Medium |
|
|
| 635 |
Design Log Storage System |
Medium |
|
|
| 636 |
Exclusive Time of Functions |
Medium |
|
|
| 637 |
Average of Levels in Binary Tree |
Easy |
|
|
| 638 |
Shopping Offers |
Medium |
|
|
| 639 |
Decode Ways II |
Hard |
|
|
| 640 |
Solve the Equation |
Medium |
|
|
| 642 |
Design Search Autocomplete System |
Hard |
|
|
| 643 |
Maximum Average Subarray I |
Easy |
|
|
| 644 |
Maximum Average Subarray II |
Hard |
|
|
| 645 |
Set Mismatch |
Easy |
|
|
| 646 |
Maximum Length of Pair Chain |
Medium |
|
|
| 647 |
Palindromic Substrings |
Medium |
|
|
| 648 |
Replace Words |
Medium |
|
|
| 649 |
Dota2 Senate |
Medium |
|
|
| 650 |
2 Keys Keyboard |
Medium |
|
|
| 651 |
4 Keys Keyboard |
Medium |
|
|
| 652 |
Find Duplicate Subtrees |
Medium |
|
|
| 653 |
Two Sum IV - Input is a BST |
Easy |
|
|
| 654 |
Maximum Binary Tree |
Medium |
|
|
| 655 |
Print Binary Tree |
Medium |
|
|
| 656 |
Coin Path |
Hard |
|
|
| 657 |
Judge Route Circle |
Easy |
|
|
| 658 |
Find K Closest Elements |
Medium |
|
|
| 659 |
Split Array into Consecutive Subsequences |
Medium |
|
|
| 660 |
Remove 9 |
Hard |
|
|
| 661 |
Image Smoother |
Easy |
|
|
| 662 |
Maximum Width of Binary Tree |
Medium |
|
|
| 663 |
Equal Tree Partition |
Medium |
|
|
| 664 |
Strange Printer |
Hard |
|
|
| 665 |
Non-decreasing Array |
Easy |
|
|
| 666 |
Path Sum IV |
Medium |
|
|
| 667 |
Beautiful Arrangement II |
Medium |
|
|
| 668 |
Kth Smallest Number in Multiplication Table |
Hard |
|
|
| 669 |
Trim a Binary Search Tree |
Easy |
|
|
| 670 |
Maximum Swap |
Medium |
|
|
| 671 |
Second Minimum Node In a Binary Tree |
Easy |
|
|
| 672 |
Bulb Switcher II |
Medium |
|
|
| 673 |
Number of Longest Increasing Subsequence |
Medium |
|
|
| 674 |
Longest Continuous Increasing Subsequence |
Easy |
|
|
| 675 |
Cut Off Trees for Golf Event |
Hard |
|
|
| 676 |
Implement Magic Dictionary |
Medium |
✓ |
|
| 677 |
Map Sum Pairs |
Medium |
|
|
| 678 |
Valid Parenthesis String |
Medium |
|
|
| 679 |
24 Game |
Hard |
|
|
| 680 |
Valid Palindrome II |
Easy |
|
|
| 681 |
Next Closest Time |
Medium |
✓ |
✓ |
| 682 |
Baseball Game |
Easy |
|
|
| 683 |
K Empty Slots |
Hard |
✓ |
|
| 684 |
Redundant Connection |
Medium |
|
|
| 685 |
Redundant Connection II |
Hard |
|
|
| 686 |
Repeated String Match |
Easy |
|
|
| 687 |
Longest Univalue Path |
Easy |
|
|
| 688 |
Knight Probability in Chessboard |
Medium |
|
|
| 689 |
Maximum Sum of 3 Non-Overlapping Subarrays |
Hard |
|
|
| 690 |
Employee Importance |
Easy |
|
|
| 691 |
Stickers to Spell Word |
Hard |
|
|
| 692 |
Top K Frequent Words |
Medium |
✓ |
|
| 693 |
Binary Number with Alternating Bits |
Easy |
|
|
| 694 |
Number of Distinct Islands |
Medium |
|
|
| 695 |
Max Area of Island |
Easy |
|
|
| 696 |
Count Binary Substrings |
Easy |
|
|
| 697 |
Degree of an Array |
Easy |
|
|
| 698 |
Partition to K Equal Sum Subsets |
Medium |
|
|
| 699 |
Falling Squares |
Hard |
|
|